64 Bit Snapshot ================ | **Block:** 64 Bit Snapshot (``snap64``) | **Block Author**: Aaron Parsons | **Document Author**: Aaron Parsons, Ben Blackman +--------------------------------------------------------------------------+ | .. raw:: html | | | |
| | | | .. rubric:: Contents | | :name: contents | | | | .. raw:: html | | | |
| | | | - `Summary <#summary>`__ | | - `Mask Parameters <#mask-parameters>`__ | | - `Ports <#ports>`__ | | - `Description <#description>`__ | | | | - `Usage <#usage>`__ | +--------------------------------------------------------------------------+ Summary --------- The snap block provides a packaged solution for capturing data from the FPGA fabric and making it accessible from the CPU. Snap64 captures to 2x32 bit wide shared BRAMs to effect a 64 bit capture. Mask Parameters ---------------- +--------------------------------+------------+-------------------------------------------------------------------------------------------------------------+ | Parameter | Variable | Description | +================================+============+=============================================================================================================+ | No. of Samples (2\ :sup:`?`) | nsamples | Specifies the depth of the Shared BRAM(s); i.e. the number of 64bit samples which are stored per capture. | +--------------------------------+------------+-------------------------------------------------------------------------------------------------------------+ Ports ------ +--------+-------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------+ | Port | Dir | Data Type | Description | +========+=======+===================+===============================================================================================================================================+ | din | IN | unsigned\_64\_0 | The data to be captured. Regardless of type, the bit-level representation of these numbers are written as 64bit values to the Shared BRAMs. | +--------+-------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------+ | trig | IN | boolean | When high, triggers the beginning of a data capture. Thereafter, every enabled data is written to the shared BRAM until it is full. | +--------+-------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------+ | we | IN | boolean | After a trigger is begun, enables a write to Shared BRAM. | +--------+-------+-------------------+-----------------------------------------------------------------------------------------------------------------------------------------------+ Description ------------ Usage ^^^^^^^^ Under TinySH/BORPH, this device will have 3 sub-devices: ``ctrl``, ``bram_msb``, ``bram_lsb``, and ``addr``. ``ctrl`` is an input register. Bit 0, when driven from low to high, enables a trigger/data capture to occur. Bit 1, when high, overrides ``trig`` to trigger instantly. Bit 2, when high, overrides ``we`` to always write data to bram. ``addr`` is an output register and records the last address of bram to which data was written. ``bram_msb`` and ``bram_lsb`` are 32 bit wide Shared BRAMs of the depth specified in ``Parameters``. ``bram_msb`` holds the upper 32 bits of ``din`` while ``bram_lsb`` holds the lower 32 bits of ``din``.